Tesla Powerwall 3 vs Fox ESS EVO 10
Tesla Powerwall 3 stores 13.5 kWh per unit, expanding to 94.5 kWh. Fox ESS EVO 10 stores 9.73 kWh per unit, expanding to 29.18 kWh. Across the setups we list, continuous power is 11.04 kW for the Powerwall 3 and 5–10 kW for the EVO 10. Warranty: 10 years vs 12 years. Intelligent Octopus Flux: Powerwall 3 is “On Octopus's integration list”; EVO 10 is “Sold by Octopus for this tariff; not on its FAQ list”.
Figures from manufacturer documents, last checked 26 Sept 2026. We don't rank products or take payment for results.
How they're built
Tesla Powerwall 3
All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side).
Backup: Backup Gateway 2 (required for backup installs).
Fox ESS EVO 10
All-in-one: battery with built-in hybrid inverter (solar connects on the DC side).
Backup: Built-in EPS (backup) output.
Side by side
| Specification | Tesla Powerwall 3 | Fox ESS EVO 10 |
|---|---|---|
| Usable capacity (per unit) | 13.5 kWhAC, minimum at beginning of life, 25°CTesla datasheet, p.2 & p.4 | 9.73 kWhcalculatedCalculated; the datasheet gives total energy and depth of discharge, not usable energyFox ESS datasheet, p.2, Battery Connection |
| Battery chemistry | Not documented | LFP (LiFePO₄)Fox ESS datasheet, p.2 |
| Maximum usable storage (expanded) | 94.5 kWhMultiple Powerwall 3 units and/or ExpansionsTesla datasheet, p.1 | 29.18 kWhcalculatedCalculated from parallel limit and usable capacityFox ESS datasheet |
| How it expands | Up to 4 Powerwall 3 units and up to 3 Expansion units (max 7 units)Tesla datasheet, p.2 | Up to 3 EVO units in parallelFox ESS datasheet, p.2, EPS output: Parallel operation |
| Continuous power (per unit) | 11.04 kWInstaller-configurable: 3.68, 5, 6, 7, 8, 9, 10 or 11.04 kWTesla datasheet, p.2, Nominal AC Output Power at 230 V | 5–10 kWEVO 10-5-H: 5 kW · EVO 10-8-H: 8 kW · EVO 10-10-H: 10 kWFox ESS datasheet, p.2, AC output rated power |
| Peak power | Not documented | 10–20 kWBackup (EPS) peak for 10 seconds: 10 / 16 / 20 kVA by modelFox ESS datasheet, p.2, EPS output |
| Round-trip efficiency | 89%Solar → battery → home/grid, typical use caseTesla datasheet, p.2, footnotes 1 & 3 | Not documented |
| Architecture | All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side)Tesla datasheet, p.1 & p.3 solar specifications | All-in-one: battery with built-in hybrid inverter (solar connects on the DC side)Fox ESS datasheet, p.1 |
| Max solar input | 20 kWMaximum solar STC inputTesla datasheet, p.3 | 16–20 kWMax PV array: 16 kWp (5 kW model), 20 kWp (8 and 10 kW models)Fox ESS datasheet, p.2, PV input |
| Backup switchover time | Not documented | 4 msLess than 4 msFox ESS datasheet, p.2, EPS switch time |
| Backup needs | Backup Gateway 2 (required for backup installs)Tesla datasheet, p.2 & p.5 | Built-in EPS (backup) outputFox ESS datasheet, p.1–2 |
| Indoor / outdoor | Indoor and outdoor ratedTesla datasheet, p.3 | Indoor and outdoor (IP66)calculatedFox ESS datasheet, p.2 |
| Dimensions | 1105 × 609 × 193H × W × D as listedTesla datasheet, p.3 | 584 × 1009 × 197W × H × DFox ESS datasheet, p.2 |
| Weight | 130 kgTesla datasheet, p.3 | 113 kgFox ESS datasheet, p.2 |
| Warranty (UK) | 10 yearsMust be reliably connected to the internet for the full 10 yearsTesla datasheet, p.2, footnote 6 | 12 yearsFox ESS warranty, p.2, performance warranty table |
| Capacity guaranteed at end of warranty | 80%80% of 13.5 kWh at 10 yearsTesla warranty, p.1, retention table for Austria, Belgium, France, Germany, Ireland, Luxembourg, Netherlands, Switzerland or the UK | 70%70% of nominal energyFox ESS warranty, p.2 |
| Warranty conditions | Unlimited cycles for solar self-consumption, time-based control and backup; 37.8 MWh throughput limit for other uses. Minimum 4-year cover if not kept online.Tesla warranty, p.1 & p.3 | Not documented |
How long each runs your home in a power cut
Every setup we list for both, from a full battery with no solar. Appliance figures are typical estimates; use the calculator below with your own.
| Setup | Usable | Continuous | Essentials (fridge-freezer, lights, Wi-Fi, TV, charging) | Essentials + air-source heat pump (winter) |
|---|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | 11.04 kW | 3 days 10 hours | 7.7 hours |
| Tesla Powerwall 3 + 1 Expansion | 27 kWh | 11.04 kW | 6 days 20 hours | 15.5 hours |
| Tesla Powerwall 3 + 2 Expansions | 40.5 kWh | 11.04 kW | 10 days 7 hours | 23.2 hours |
| Tesla Powerwall 3 + 3 Expansions | 54 kWh | 11.04 kW | 13 days 17 hours | 31 hours |
| Fox ESS EVO 10-5-H (5 kW) | 9.73 kWh | 5 kW | 2 days 11 hours | 5.6 hours |
| Fox ESS EVO 10-8-H (8 kW) | 9.73 kWh | 8 kW | 2 days 11 hours | 5.6 hours |
| Fox ESS EVO 10-10-H (10 kW) | 9.73 kWh | 10 kW | 2 days 11 hours | 5.6 hours |
Try your own appliances
Average draw 156 W from 12.83 kWh available.
Everything on at once: 415 W — within the 11.04 kW limit
- Starts from a full battery with 0% held back as reserve.
- 5% extra allowed for wiring and standby losses on top of the manufacturer's usable figure.
- Appliance figures are typical averages; your own may differ. Enter your own wattage for the most accurate result.
- Assumes no solar recharging during the outage.
- Powerwall 3: Battery chemistry is not stated in the UK datasheet.
- Powerwall 3: A peak power figure in kW is not stated in the UK datasheet; it lists motor-start capability of 185 A (locked rotor amps).
- Powerwall 3: Continuous output is set by the installer (3.68–11.04 kW). Ask what yours will be set to.
- EVO 10: Usable capacity is calculated (10.24 kWh × 95% depth of discharge); Fox ESS does not state a usable figure in this datasheet.
- EVO 10: Round-trip efficiency is not stated; the datasheet gives a 96.4% battery-to-AC figure at full load, which is one direction only.
Questions people ask
Which stores more, Tesla Powerwall 3 or Fox ESS EVO 10?
Tesla Powerwall 3 has the higher stated maximum. Tesla Powerwall 3: up to 94.5 kWh (multiple Powerwall 3 units and/or Expansions). Fox ESS EVO 10: up to 29.18 kWh (calculated from parallel limit and usable capacity). Per unit, Tesla Powerwall 3 stores 13.5 kWh and Fox ESS EVO 10 stores 9.73 kWh.
Which can run more appliances at once?
Across the setups we list, Tesla Powerwall 3 delivers 11.04 kW continuously and Fox ESS EVO 10 delivers 5–10 kW. These are the maximums for each setup; installers can set some systems lower. Continuous power limits how many appliances can run at the same time; capacity decides how long they run.
Which has the better warranty?
Tesla Powerwall 3: 10 years, 80% capacity guaranteed at the end. Fox ESS EVO 10: 12 years, 70% capacity guaranteed at the end. Conditions differ, so check the warranty rows in the table above.
Do Tesla Powerwall 3 and Fox ESS EVO 10 work with Intelligent Octopus Flux?
Tesla Powerwall 3: On Octopus's integration list. Fox ESS EVO 10: Sold by Octopus for this tariff; not on its FAQ list. Octopus lists the battery brands it can control in its Intelligent Flux FAQ; see our Intelligent Octopus Flux page for details.
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Sources
- Powerwall 3 Datasheet (UK) — Tesla, 2026. Retrieved 26 Sept 2026.
- Powerwall Limited Warranty (Europe incl. UK) — Tesla, Rev. 1.16, effective 3 Dec 2025. Retrieved 26 Sept 2026.
- EVO 10 Datasheet (UK) V1.0 — Fox ESS, V1.0. Retrieved 26 Sept 2026.
- Fox ESS Battery Warranty Policy (UK) Version 4.5 — Fox ESS, 4.5. Retrieved 26 Sept 2026.
- Intelligent Octopus Flux: Frequently Asked Questions — Octopus Energy. Retrieved 26 Sept 2026.
Spotted an error? See how we check data. Always confirm your final design with an MCS-certified installer.